Our ancestors may have lived on continents other than Africa much earlier than scientists previously thought.

Archaeologists recently excavated stone tools in Shangchen, China, that were made about 2.12 million years ago, LiveScience reported Wednesday. While the common theory is that hominins didn't leave Africa until about 1.8 million years ago, the finding would suggest that they were in fact on the move much earlier.

"It suggests a way earlier migration out of Africa than we ever would have imagined," Michael Petraglia, a paleoanthropologist at the Max Planck Institute for the Science of Human History, told LiveScience.

The researchers, from China and the U.K., found quartz stones that nearly look like naturally produced sediment formations. But upon closer inspection, the stones flaked in such a way that suggests they were shaped by human hands. Scientists are still working to determine exactly how old the artifacts are, and to verify that they really are evidence of a human presence in ancient China.

Homo erectus, or even some earlier species of hominin, had to have migrated out of Africa roughly 10,000 generations earlier than scientists thought, the finding suggests. "It really opens all sorts of questions with respect to migrations out of Africa and the ability of these humans to adapt to various ecological circumstances," said Petraglia. Read more at LiveScience. Summer Meza